Submission #1262417

#	Time	Username	Problem	Language	Result	Execution time	Memory
1262417		EntityPlantt	Senior Postmen (BOI14_postmen)	C++20	100 / 100	495 ms	160460 KiB

postmen

#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("Ofast,unroll-loops,O2")

constexpr int N = 5e5;
int vis[N];
bitset<N> path;
set<int> connected, g[N];

int dfs(int u) {
	path.set(u);
	while (!g[u].empty()) {
		int v = *g[u].begin();
		g[v].erase(u);
		if (g[v].empty()) connected.erase(v);
		g[u].erase(g[u].begin());
		if (g[u].empty()) connected.erase(u);
		if (path.test(v)) {
			path.reset(u);
			cout << u + 1 << ' ';
			return v;
		}
		int r = dfs(v);
		if (r != u) {
			path.reset(u);
			cout << u + 1 << ' ';
			return r;
		}
		else cout << u + 1 << '\n';
	}
	return -1;
}

signed main() {
	ios::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	int n, m;
	cin >> n >> m;
	while (m--) {
		int a, b;
		cin >> a >> b;
		g[--a].insert(--b);
		g[b].insert(a);
	}
	for (int i = 0; i < n; i++) if (!g[i].empty()) connected.insert(i);
	while (!connected.empty()) dfs(*connected.begin());
}

• Subtask 1: 38 / 38
• Subtask 2: 17 / 17
• Subtask 3: 45 / 45